Minoxidil comes as a liquid solution or foam applied to the scalp once or twice daily to maintain or reduce the rate of hair loss. This slowing of hair loss occurs for the majority of Minoxidil patients; a smaller minority re-grow some hair as well. Its most common side effect is scalp irritation. The earlier Minoxidil is used to treat hair loss, the more effective it is to help treat male or female pattern hair loss. Patients can lose the hair regained or maintained about four to six months after they stop using Minoxidil; it will not promote further hair loss itself if stopped.